diff options
| author | Mark Johnston <markj@FreeBSD.org> | 2021-07-16 10:05:28 -0400 |
|---|---|---|
| committer | Brian Behlendorf <behlendorf1@llnl.gov> | 2021-08-31 10:30:21 -0700 |
| commit | 1d2eccb67a657a67584b815ff2a2f5f9b9614821 (patch) | |
| tree | 8e608e13bd9fad3d3977eb53170697cca6cd6b67 | |
| parent | 951aef3cd51c7f59034288d9cb242fe43a1e476f (diff) | |
Zero pad bytes following TX_WRITE log data
When logging a TX_WRITE record in the case where file data has to be
copied from the DMU, we pad the log record size to a multiple of 8
bytes. In this case, any padding bytes should be zeroed, otherwise the
contents of uninitialized memory are written to the ZIL.
This was found using KMSAN.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Mark Johnston <markj@FreeBSD.org>
Closes #12383
| -rw-r--r-- | module/zfs/zil.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/module/zfs/zil.c b/module/zfs/zil.c index e535cae69..2e752c1db 100644 --- a/module/zfs/zil.c +++ b/module/zfs/zil.c @@ -1617,7 +1617,7 @@ zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb) lr_t *lrcb, *lrc; lr_write_t *lrwb, *lrw; char *lr_buf; - uint64_t dlen, dnow, lwb_sp, reclen, txg, max_log_data; + uint64_t dlen, dnow, dpad, lwb_sp, reclen, txg, max_log_data; ASSERT(MUTEX_HELD(&zilog->zl_issuer_lock)); ASSERT3P(lwb, !=, NULL); @@ -1651,8 +1651,9 @@ zil_lwb_commit(zilog_t *zilog, itx_t *itx, lwb_t *lwb) if (lrc->lrc_txtype == TX_WRITE && itx->itx_wr_state == WR_NEED_COPY) { dlen = P2ROUNDUP_TYPED( lrw->lr_length, sizeof (uint64_t), uint64_t); + dpad = dlen - lrw->lr_length; } else { - dlen = 0; + dlen = dpad = 0; } reclen = lrc->lrc_reclen; zilog->zl_cur_used += (reclen + dlen); @@ -1746,6 +1747,9 @@ cont: error = zilog->zl_get_data(itx->itx_private, itx->itx_gen, lrwb, dbuf, lwb, lwb->lwb_write_zio); + if (dbuf != NULL && error == 0 && dnow == dlen) + /* Zero any padding bytes in the last block. */ + bzero((char *)dbuf + lrwb->lr_length, dpad); if (error == EIO) { txg_wait_synced(zilog->zl_dmu_pool, txg); |